scholarly journals Spatial and temporal distribution of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) and Euxesta spp. (Diptera: Otitidae) in the corn crop

2021 ◽  
Vol 14 ◽  
pp. e919
Author(s):  
Jessica Vasconcelos Ferreira ◽  
Ivan Carlos Fernandes Martins ◽  
Raiana Rocha Pereira ◽  
Rayane Rocha Pereira ◽  
Mateus Higo Daves Alves ◽  
...  
Keyword(s):  
Spatial Dependence ◽  
Helicoverpa Zea ◽  
Reproductive Period ◽  
Corn Earworm ◽  
Spatial Behavior ◽  
Sample Population ◽  
Distribution Models ◽  
Corn Silk ◽  
Corn Crop ◽  
Area Of Influence

The aim of this study was to verify the pattern and the spatial and temporal behavior of the corn earworm and corn-silk fly in the corn crop. Hybrid corn was planted without chemical insect control in one hectare, this area was divided into 100 plots of 100 m². For the occurrence of Euxesta spp. all parts of the plants were visually analyzed, whereas for Helicoverpa zea (Boddie) 10 ears were removed at random from each plot, totaling 1,000 ears per sample. Population fluctuation was related to the phenological stages of corn. For spatial behavior, the dispersion indices, frequency distribution models and geostatistics (Krigagem) were analyzed. The corn earworm (small and large) and corn-silk fly showed aggregate pattern and spatial behavior. The reach of caterpillars <1 cm had an area of influence greater than caterpillars > 1 cm, with spatial dependence being considered moderate. The corn-silk fly had a maximum area of influence of 1.33 ha with moderate and weak spatial dependence. The maps demonstrated that these insects occur dispersed throughout the corn area, but with aggregations influenced by the adjacent areas and edges of the crop. The largest occurrence of corn earworms was at the R3 stage. It was also found that the corn-silk fly followed the occurrence of the corn earworm. It is concluded that the studied pests have an aggregate spatial tendency in the corn crop and with the influence of adjacent areas, in addition to presenting related population peaks in the reproductive period of the corn crop.

scholarly journals Spatial behavior of corn leaf aphid and syrphid flies in corn crop in the northeast of Pará

2020 ◽  
Vol 13 ◽  
pp. e0872
Author(s):  
José Marlon dos Santos Nascimento ◽  
Ivan Carlos Fernandes Martins ◽  
Marcello Neiva De Mello ◽  
Jhonatan Rocha Da Silva ◽  
Maria Milena Oliveira Lima ◽  
...  
Keyword(s):  
Spatial Dependence ◽  
Secondary Forest ◽  
Spatial Interaction ◽  
Spatial Behavior ◽  
Kriging Interpolation ◽  
Exponential Models ◽  
Aggregate Behavior ◽  
Corn Crop ◽  
Corn Leaf Aphid ◽  
Syrphid Flies

The aim of this study was to verify the spatial and temporal behavior of corn leaf aphid (Rhopalosiphum maidis Fitch.) and hoverflies in corn crop in the municipality of Igarapé-Açu, northeast of Pará, Brazil, as well as the influence of adjacent areas on the occurrence of these insects. An experimental area of 1.0 ha (100 x 100 m) was used in the years 2015 and 2016, adjacent areas consisted of mango agroecosystem, pasture and secondary forest. The area was divided into grid with 100 plots of 100 m² (10 x 10 m). Ten plants were randomly selected, totaling 1,000 plants per sampling date. Corn leaf aphid colonies (= or> 15 aphid) and syrphid flies adult was visually analyzed throughout the aerial parts of the plants. The spatial behavior was analyzed by semivariogram modeling and kriging interpolation maps. The semivariograms and kriging maps were made by the R software for Windows. Gaussian, spherical and exponential models were the best fit for corn leaf aphid in both harvests, showing aggregate behavior. The strong and moderate spatial dependence index prevailed, with range ranging from 12.46 to 93.04 m for R. maidis. The syrphids flies showed spatial interaction with the corn leaf aphid and they also show aggregate behavior, confirmed by most adjustments in the spherical and exponential models. The spatial dependence index of the prevailing syrphids flies were moderate and weak, ranging from 14.00 to 101.33 m. Adjacent areas showed influence on occurrence and dispersal of both corn leaf aphid and syrphids flies.

scholarly journals A Field Test of Corn Cultivars for Insect and Disease Resistance

1969 ◽  
Vol 61 (3) ◽  
pp. 319-325
Author(s):  
O. J. Webster ◽  
D. W. Walker
Keyword(s):  
Puerto Rico ◽  
Disease Resistance ◽  
Field Test ◽  
Corn Earworm ◽  
Pests And Diseases ◽  
Corn Silk ◽  
Sugarcane Borer ◽  
Pest Infestation ◽  
Corn Crop ◽  
Corn Pests

Eighteen corn cultivars were tested for resistance to three corn pests (corn earworm, sugarcane borer, and corn silk maggot), and two diseases (corn rust and corn blight) at Mayagüez, Puerto Rico. Armyworm control with methomyl was necessary to produce a corn crop. Eighteen cultivars from Georgia were less resistant to pests and diseases than Mayorbela, Ibadan A, and Ibadan B. Significant differences were found between sprayed and unsprayed plots in yield and pest infestation.

Effect of Cuticular Lipids From Silks of Selected Corn Genotypes on the Development of Corn Earworm Larvae

1994 ◽  
Vol 29 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Guang Yang ◽  
B. R. Wiseman ◽  
Karl E. Espelie
Keyword(s):  
Helicoverpa Zea ◽  
Zea Mays L ◽  
Control Diet ◽  
Larval Growth ◽  
Adult Emergence ◽  
Corn Earworm ◽  
Cuticular Lipids ◽  
Cuticular Lipid ◽  
Corn Silk ◽  
Meridic Diet

Eleven genotypes of corn, Zea mays L., known to vary in their resistance to silk-feeding by larvae of the corn earworm, Helicoverpa zea (Boddie), were used to study the effect of corn silk cuticular lipids on larval growth and development. Growth of the corn earworm was significantly enhanced when larvae were reared on meridic diet containing corn silks from which the cuticular lipids had been removed. Growth of larvae reared on a diet containing unextracted silks from genotypes ‘Stowell's’ ‘Evergreen’, ‘Pioneer 3369A’, and ‘PI340856’ was not affected. When the cuticular lipid extracts of corn silks were added to a meridic diet, no significant differences were found in the weight of 8-day larvae, time to pupation, or days to adult emergence for larvae reared on silks of several corn genotypes. However, the weight of pupae was significantly less when larvae were fed a diet containing cuticular lipids extracted from silks of three corn genotypes ‘Stowell's Evergreen’, ‘GE37’, and ‘Zapalote Chico 2451#(P)C3’ than the weight of pupae from larvae that fed on the control diet.

scholarly journals Genetic Mechanisms Underlying Apimaysin and Maysin Synthesis and Corn Earworm Antibiosis in Maize (Zea mays L.)

Genetics ◽  
1998 ◽  
Vol 149 (4) ◽  
pp. 1997-2006
Author(s):  
E A Lee ◽  
P F Byrne ◽  
M D McMullen ◽  
M E Snook ◽  
B R Wiseman ◽  
...  
Keyword(s):  
Helicoverpa Zea ◽  
Larval Growth ◽  
Corn Earworm ◽  
Phenotypic Variance ◽  
Significant Qtls ◽  
F2 Population ◽  
Genetic Mechanisms ◽  
Trait Locus ◽  
Maize Silks ◽  
Related Compounds

Abstract C-glycosyl flavones in maize silks confer resistance (i.e., antibiosis) to corn earworm (Helicoverpa zea [Boddie]) larvae and are distinguished by their B-ring substitutions, with maysin and apimaysin being the di- and monohydroxy B-ring forms, respectively. Herein, we examine the genetic mechanisms underlying the synthesis of maysin and apimaysin and the corresponding effects on corn earworm larval growth. Using an F2 population, we found a quantitative trait locus (QTL), rem1, which accounted for 55.3% of the phenotypic variance for maysin, and a QTL, pr1, which explained 64.7% of the phenotypic variance for apimaysin. The maysin QTL did not affect apimaysin synthesis, and the apimaysin QTL did not affect maysin synthesis, suggesting that the synthesis of these closely related compounds occurs independently. The two QTLs, rem1 and pr1, were involved in a significant epistatic interaction for total flavones, suggesting that a ceiling exists governing the total possible amount of C-glycosyl flavone. The maysin and apimaysin QTLs were significant QTLs for corn earworm antibiosis, accounting for 14.1% (rem1) and 14.7% (pr1) of the phenotypic variation. An additional QTL, represented by umc85 on the short arm of chromosome 6, affected antibiosis (R2 = 15.2%), but did not affect the synthesis of the C-glycosyl flavones.

scholarly journals An Advanced Numerical Trajectory Model Tracks a Corn Earworm Moth Migration Event in Texas, USA

Insects ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 115 ◽  
Author(s):  
Qiu-Lin Wu ◽  
Gao Hu ◽  
John Westbrook ◽  
Gregory Sword ◽  
Bao-Ping Zhai
Keyword(s):  
Helicoverpa Zea ◽  
Wrf Model ◽  
Weather Conditions ◽  
Computational Design ◽  
Corn Earworm ◽  
Long Distance ◽  
Hysplit Model ◽  
Trajectory Model ◽  
Trajectory Simulation ◽  
Migration Event

Many methods for trajectory simulation, such as Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT), have been developed over the past several decades and contributed greatly to our knowledge in insect migratory movement. To improve the accuracy of trajectory simulation, we developed a new numerical trajectory model, in which the self-powered flight behaviors of insects are considered and trajectory calculation is driven by high spatio-temporal resolution weather conditions simulated by the Weather Research and Forecasting (WRF) model. However, a rigorous evaluation of the accuracy of different trajectory models on simulated long-distance migration is lacking. Hence, in this study our trajectory model was evaluated by a migration event of the corn earworm moth, Helicoverpa zea, in Texas, USA on 20–22 March 1995. The results indicate that the simulated migration trajectories are in good agreement with occurrences of all pollen-marked male H. zea immigrants monitored in pheromone traps. Statistical comparisons in the present study suggest that our model performed better than the popularly-used HYSPLIT model in simulating migration trajectories of H. zea. This study also shows the importance of high-resolution atmospheric data and a full understanding of migration behaviors to the computational design of models that simulate migration trajectories of highly-flying insects.

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